Hansoh Pharmaceutical Group Co., Ltd. has announced positive Phase 2 clinical trial results for HS-20089 (also known as GSK5733584), a B7-H4-targeted antibody-drug conjugate $(ADC)$, in patients with platinum-resistant ovarian cancer $(PROC)$. The findings were presented as an oral presentation at the 2025 International Gynecologic Cancer Society (IGCS) Annual Global Meeting and were previously shared at the 2025 European Society for Medical Oncology (ESMO) Annual Meeting. As of the June 20, 2025 data cutoff, HS-20089 demonstrated a confirmed objective response rate $(ORR)$ of 48.5% and a duration of response (DoR) of 6.8 months in heavily pretreated PROC patients, regardless of tumor B7-H4 expression. The median progression-free survival (mPFS) was 6.4 months and the median overall survival (mOS) was 14.6 months, with a median follow-up time of 11.5 months. The safety profile was consistent with previous studies, and no cases of interstitial lung disease were reported. A Phase 3 study is ongoing.